1. Technical Field of the Invention
This invention relates to a pouring closure for liquid packagings of all kinds. The liquid packagings in mind are made from foil-coated paper, in which e.g. milk, fruit juices, all kinds of non-alcoholic beverages or other liquids in general are packed. The usual volumes of such liquid packagings range from 0.125 to 2 liters. Plastic pouring closures for packagings of this kind are already known. They form a pouring stem with an edge projecting radially from the bottom edge and an outer thread on the stem. A threaded cap is screwed onto the stem as a closure. This pouring stem is introduced into the top limiting surface of the packaging from below, via a hole, and the top side of the projecting edge is welded to the underside of the limiting surface by means of ultrasound, causing the plastic coating to join sealingly with the projecting edge of the stem. The packaging is then machine-sealed, filled, and the threaded cap is screwed onto the stem. One preferred packaging form has vertical sides which extend slightly beyond the top horizontal limiting surface of the packaging, thereby forming a rimmed edge or a rim of about 2 to 5 mm, which results from the technical production process, but also gives the packaging an elegant appearance whilst furthermore ensuring it can be stacked. In the case of a pouring closure for this type of packaging, it is important that the height of the pouring stem extends beyond the rim as far as necessary to achieve a reliable pouring geometry in order to ensure reliable pouring. This type of pouring geometry is achieved when, with the stem open and the packaging tilted slowly into the pouring position, the flow of poured liquid always reaches reliably beyond the rim, and no liquid ends up in the area inside the rim and hence on the top limiting surface. Furthermore, the pouring stem also has to be designed so that it does not attract the liquid during pouring due to capillary effects and surface tension, with the result that the latter runs e.g. down the outside of the stem and ends up, when the packaging is tilted back, collecting on the top limiting surface and inside the rim. Depending on the horizontal distance of the stem from the rim when the packaging is in an upright position, the stem has to extend beyond the rim to a greater or lesser degree in order to ensure a reliably functioning pouring geometry.
2. Description of the Prior Art
Conventional pouring closures of the type described above consist of only two elements, namely a stem with a radial projection at the bottom and a matching threaded cap. Their pouring geometry leaves something to be desired, and these conventional pouring closures also mean that packagings fitted with them cannot be stacked. If two packagings are stacked on top of each other, the bottom of the top packaging rests on the top of the cap of the packaging underneath, instead of only on the rim running round the top limiting surface. Because liquid packagings with conventional pouring closures cannot be stacked, cardboard boxes, crates or cages made from wood, plastic or metal are required to accommodate the liquid packagings; these can then be stacked irrespective of their contents. It would be desirable if cardboard trays with a low rim could be used; the liquid packagings would be arranged in rows on the trays so that each tray could rest directly on the liquid packagings arranged in rows on a tray underneath. Several such cardboard trays could then be stacked on top of each other, with six-unit and twelve-unit trays as already in use now being suitable, although they could not be stacked on top of the liquid packagings in another tray if said packagings are fitted with a conventional pouring closure. It would be desirable, therefore, to achieve this stackability and still be able to handle, transport and store the packagings reliably. If the bottom of each upper tray were to rest as desired on the rims of the packagings below, several trays filled with liquid packagings arranged in rows could be stacked directly on top of each other. The weight of the upper trays would be distributed over the peripheral walls of all the packagings below. Prior art pouring closures prevent such stacking because they have to project beyond the rim to ensure the pouring geometry. The general aim is to design the pouring closures to be as low as possible and to ensure that the trays can be stacked.